The purpose of this proposal is to demonstrate the capabilities of the University of Pittsburgh they apply to participation in a multicenter network of maternal-fetal medicine units. As an active participant in the current Network of Maternal Fetal Medicine Units, we have demonstrated our willingness to Cooperate with other institutions and the NICHD in the development and implementation of clinical research protocols. We have been actively involved in all aspects of Network activities' and have served on the subcommittee of every protocol underway or in preparation. We have written the protocol for the use of aspirin to prevent preeclampsia in women with complications of pregnancy. The Division of Maternal Fetal Medicine is composed of seven specialists in Maternal Fetal Medicine. Each person is committed to the Network and has assisted in recruitment. The obstetrical unit of the University of Pittsburgh is the largest private obstetrical service in the United States with more than 10,000 deliveries annually. In 1989,approximately 4500 patients qualified as high risk including 2039 women with preterm labor, 323 women with diabetes, 875 women with preeclampsia or hypertension, 331 women with third trimester bleeding, 272 women with cardiac disease, 153 women, with severely growth retarded fetuses and 250 women with multifetal pregnancies. Approximately 2300 women delivering at the University of Pittsburgh are indigent, 1600 are black or Hispanic and 8400 are white, most of which have third party insurance. This wide diversity of patients makes our institution particularly well suited to performance of clinical studies.